Studies on the mechanism of luteinizing hormone-induced expression of prostaglandin E2 receptor EP4b essential for ovulation of the medaka [an abstract of dissertation and a summary of dissertation review]Studies on the mechanism of luteinizing hormone-induced expression of prostaglandin E2 receptor EP4b essential for ovulation of the medaka [an abstract of dissertation and a summary of dissertation review]メダカ排卵に必須なプロスタグランジンE2受容体EP4bのLHによる発現誘導機構に関する研究 [論文内容及び審査の要旨]